@client.event
async def on_message(message):
  if message.author == client.user:
    return

  if message.content.startswith('$hello'):
    await message.channel.send('Hello!')

@client.command(pass_context = True)
async def join(ctx):
    if (ctx.author.voice):
        channel = ctx.message.author.voice.channel
        await channel.connect()
    else:
        await ctx.send('You are not in a voice channel, you must be in a voice channel to run this command!')

@client.command(pass_context = True)
async def leave(ctx):
    if (ctx.voice_client):
        await ctx.guild.voice_client.disconnect()
        await ctx.send('I left the Voice Channel')
    else:
        await ctx.send("I am not in a voice channel")

Its only the async def parts thats having this error.